Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, data, and so on. These systems may be multiple-access systems capable of supporting simultaneous communication of multiple terminals with one or more base stations.
As used herein, the term “user equipment” refers to an electronic device that may be used for voice and/or data communication over a wireless communication network. Examples of user equipment include cellular phones, personal digital assistants (PDAs), handheld devices, wireless modems, laptop computers, personal computers, etc. A user equipment may alternatively be referred to as a mobile station, a mobile terminal, a subscriber station, a remote station, a user terminal, a terminal, an access terminal, a subscriber unit, etc.
A wireless communication network may provide communication for a number of user equipments, each of which may be serviced by a base station. A base station may alternatively be referred to as an access point, a Node B, or some other terminology.
A base station may be part of an access network. An access network may include one or more base stations with the same network operator. Each of the base stations in an access network may use the same radio access technology (RAT). A user equipment may connect to a base station within an access network if the user equipment has a service level agreement (SLA) with the network operator.
With the current number of RATs available for consumer use being fairly low, a user equipment may scan all the available access networks before deciding on which access network (and corresponding RAT) is best. However, new techniques such as software defined radio and developments to decouple the core network from the access network may boost the development of more RATs. Multi-mode chipsets may enable this development. As the number of RATs increases, a user equipment may have to check more and more supported access networks to determine the optimal access network. This method may be time and battery power consuming.
Procedures for inter-operator handovers (including those that are inter-RAT) have been addressed by the 3rd Generation Partnership Project (3GPP). The Access Network Discovery and Support Function (ANDSF) has been introduced, thereby providing information on available networks and policies to a user equipment. However, the ANDSF belongs to an operator and is thus not suited to determine the best available access network for a user equipment among different network operators.
A further trend in 3GPP is the introduction of client based mobility. Client based mobility eases inter-RAT handovers from a technical perspective. Although network operators may cooperate sufficiently to enable inter-operator handovers and inter-operator, inter-RAT handovers, network operators may not cooperate enough to determine the best available access network for the UE. Accelerated and efficient access network selection may lead to a better user experience by creating service continuity with seamless handovers.